Re: ORGLIST: Schiff bases

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From: Witek Mozga (mozgaw$##$rocketmail.com)
Date: Wed Jun 21 2000 - 12:30:49 EDT

Hello Kamil,

I once performed the synthesis of benzylamine amide in CH2Cl2
and observed benzaldehyde formation. I explained it to myself that
the amine reacted with CH2Cl2 to give imine:

Ph-CH2-NH=CH2

that was in equilibrium with the form in which the double bond
migrated to give the more stable conjugated system:

Ph-CH2-NH=CH2 <-> Ph-CH2=NH-CH3

after aqueous workup the latter compound hydrolysed to give
benzaldehyde and methylamine.

If I am right it means that CH2Cl2 is not so "neutral" solvent for
amines afterall. What do you think?

Best regards,
Witek

Pozdrowienia z Lodzi.

> Hello, I have some problems with salophenes (Schiff bases). The
> problem is as follows: the synthesis of salophene from salicylaldehyde
> and o-phenylenediamine is performed in MeOH/CH2Cl2. But once
> synthesised, when dissolved in CH2Cl2 seems to be not stable. UV/VIS
> spectra confirm that in CH2Cl2 solution the peaks from salicyaldehyde
> appears. That may indicate decomposition of salophene. But is it
> possible that so "neutral" solvent as dichloromethane is able to
> destroy the imine
> bonds ?
> Thank you in advance
> --
> Kamil Wojciechowski, Ph.D. student
> Department of Analytical Chemistry,
> Warsaw University of Technology,
> Noakowskiego 3, 00-664 Warsaw, Poland.
> Tel.: 0-22-660-56-31
> e-mail: kamilwoj$##$ch.pw.edu.pl
> kamilwoj$##$chemix.ch.pw.edu.pl
> http://www.ch.pw.edu.pl/~kamilwoj/index.html
>
>
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